segmentation.py

import logging
from typing import List, Tuple, Dict

import torch
import gc
import numpy as np
from PIL import Image

from transformers import AutoImageProcessor, UperNetForSemanticSegmentation

from palette import ade_palette

LOGGING = logging.getLogger(__name__)


def flush():
    gc.collect()
    torch.cuda.empty_cache()


def get_segmentation_pipeline() -> Tuple[AutoImageProcessor, UperNetForSemanticSegmentation]:
    """Method to load the segmentation pipeline
    Returns:
        Tuple[AutoImageProcessor, UperNetForSemanticSegmentation]: segmentation pipeline
    """
    image_processor = AutoImageProcessor.from_pretrained("openmmlab/upernet-convnext-small")
    image_segmentor = UperNetForSemanticSegmentation.from_pretrained(
        "openmmlab/upernet-convnext-small")
    return image_processor, image_segmentor


@torch.inference_mode()
@torch.autocast('cuda')
def segment_image(image: Image) -> Image:
    """Method to segment image
    Args:
        image (Image): input image
    Returns:
        Image: segmented image
    """
    image_processor, image_segmentor = get_segmentation_pipeline()
    pixel_values = image_processor(image, return_tensors="pt").pixel_values
    with torch.no_grad():
        outputs = image_segmentor(pixel_values)

    seg = image_processor.post_process_semantic_segmentation(
        outputs, target_sizes=[image.size[::-1]])[0]
    color_seg = np.zeros((seg.shape[0], seg.shape[1], 3), dtype=np.uint8)
    palette = np.array(ade_palette())
    for label, color in enumerate(palette):
        color_seg[seg == label, :] = color
    color_seg = color_seg.astype(np.uint8)
    seg_image = Image.fromarray(color_seg).convert('RGB')
    return seg_image